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Series and Application Guide

Series description and comparison

The Hydrowype family of rod scrapers and wipers address varying degrees of severity in conditions encountered in motion applications. Hydrowype wipers are typically used in relatively harsh conditions, often characterized by temperature extremes (derived either from ambient temperatures or induced from pressure/duty-cycle), presence of abrasives or other aggressive forms of contaminants, or factors that have lead to the unpreventable occurrence of rod damage or abrasion. The range is intended to provide a continuum of increasingly robust wiping solutions for increasingly extreme conditions. Many Hydrowype wipers are constructed of metal, either as a component of the material itself (for example bronze-filled polymers) or more usually in a solid, precision-machined scraping element. All Hydrowype parts are precision-turned or ground for maximum concentricity and roundness, providing for superior sharpness of scraping surfaces and precision relative to rod geometry.

The superiority of metal as the basis of a scraping/wiping solution over traditional polymer or elastomeric materials is field proven as well as supported by extensive testing. Free of the vulnerabilities of aging, embrittlement, crazing, cracking, and compression-set, a metal wiper can be expected to substantially out-perform and out-last a polymer wiper in harsh conditions. A correctly mated metal-to-metal fit allows for closer contact between rod and wiper thus avoiding “over-ride” and maximizing the potential for sustained scraping. Metal has other beneficial attributes, such as an ability to maintain a constant modulus of elasticity over time, making for conformity to rod irregularities that may result from wear and damage and emerge over time and cycles. In the presence of high pressures and temperatures that in other materials are likely to induce hardening, crazing, embrittlement and compression-set, metal will in fact increase in performance.

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A metal rod wiper regularly exposed to high temperatures will normalize, relieving internal stresses and ensuring continued suppleness to aid in rod conformity. Metal also has a sacrificial tendency, so a correctly matched softer alloy will lubricate the rod, depositing material from the wiper body around the high points and into the low points of nicks and burrs on the rod surface, thus smoothing the irregularities to prolong the life of seals.

The following are some of the wiper variations offered within the Hydrowype product family.

Rod Wipers/Scrapers (A-Series, D-Series and M-Series)

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Hydrowype rod wipers are intended to scrape clean of contaminants, the external surface (outside diameter) of hydraulic, pneumatic, landing-gear, actuator and other rod types. Available in a range of different profiles and pre-loads, the geometry and manufacture of this wiper range can be adapted to fit specific circumstances, such as low-load's to minimize breakout friction in low-pressure applications, or high-load's to take advantage of ample actuating power to maximize scraping potential. The common element of all Hydrowype wipers is the precision scraping edge along with a selectable (at time of manufacture) bore taper to permit sustained scraping throughout the intended lifespan.

Bore Wipers/Scrapers (B-Series)

Hydrowype bore scrapers are constructed as both active and passive devices and provide a precision scraping edge on the outside diameter for use in applications where a bore or cylinder interior needs to be maintained free of contaminants. Active scraping potential is achieved through the use of "c" springs installed individually or in pairs to maintain external pressure against the bore surface. Like rod wipers, bore wipers are available in standard sizes as well as custom diameters and profiles, to allow for the optimization of scraping potential in association with lifespan expectancies and wear characteristics.

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Military Specification – MS28776M2 (A-Series) Scraper Rings

The Hydrowype A-Series wiper is the standard-bearer for military specification metal scrapers/wipers. Gadjets is a qualified military suppler (QPL 5049D) with an assigned QAR, on-site inspection and packaging facilities and conformance with all required standards for manufacture, quality and inspection. The Hydrowype MS28776-M2 wiper family is the only product family offering all MS28776-M2 material offerings including Brasses, Bronzes and Copper-Beryllium, and all styles, I, II and III. Each MS26776-M2 part is inspected and certified to meet all rod-RCpressure, breakout friction, gap tolerance and light tightness stipulations set forth in the Mil-spec. Gadjets is the patent holder for the two-piece 74B410064-103 MS28776-M2 variants and is sole-source supplier for the military 4G13763-101A heavy aircraft landing gear variants of MS28776-M2 parts. Unless otherwise stipulated, we will offer a Style-1 AH line wiper (without spring) when MS28776 is requested. However wherever possible we recommend use of superior Style II and Style III, fully MS28776-M2 (A-Series) compliant wipers.

AN-Style Heavy-Duty Commercial Grade Metal Wiper - (A-Series)

The AB line of metal wipers is identical to the full MS28776-M2 series of wipers in all respects except that they are not plated with the government-stipulated Cadmium, therefore comply with regulations restricting the use of Cadmium and certain Chromates. As such, this product line offers greater economy, safety and is interchangeable with MS28776-M2 wipers. Alternative plating and Chromate options are also available, including Nickle.

M-Style Medium-Duty, Fine Particle (M-Series) Metal/Polymer Wipers

Hydrowype M-Series wipers are intended for use in medium-duty (relatively light in the context of metal wiper) applications where a light-weight, flexible wiper design will suffice and where gland space is ample. This is a relatively wide and deep profile which incorporates an elastomeric seal to ensure contaminants cannot bypass the wiper around the clearance between the wiper OD and the groove in the gland.

D-Style Ultra-Heavy-Duty (D-Series) Metal Wipers

The D-Series wiper line including the Style-DS and accompanying Style-DP elastomeric wiper, is intended for use primarily where the following conditions are to be encountered: direct contact of the wiper with ultra-heated or molten materials; severely adhered contaminants (baked into or fused with the rod surface); significant shock loading and side-loadings; and existing rod damage, where a tool-steel grade wiper is required to scrape off deflected (dislodged) rod material.

Two-piece Rod Wipers (Style-AC, Style-AG and Style-DC)

Hydrowype two-piece wipers have a wiper body that is fully broken into two halves to permit live replacement where full tear down and removal of the rod-end, clevis or linkage is not desirable. A proprietary spring is used to retain the two halves as a single working element upon installation so as to be ideal for use where the wiper is likely to encounter accelerated wear, typically from super abrasive materials or the presence of significant side load. This wiper is ideal in field maintenance-repair situations and an installation tool is available to aid in installing the spring even under the most difficult break down or maintenance conditions. The two-piece wiper is especially effective when combined with the Hydrowype Adapter or some similar means of fixing the ring in place outboard of the cylinder cap and existing packing. Thus, in retrofit situations, the adapter can simply be released from the end-cap, the spring and two halves of ring removed, and replaced with a new wiper.

Installation Adapters (AD-series)

For all A-Series (MS28776-M2 or AN) interchangeable wipers, the Hydrowype Adapter kit is available comprising a keeper plate and follower plate pair, to secure the wiper outboard of the cylinder end-cap or gland. These adapters are provided in plated or coated sheet formed metal, complete with the necessary profile to effectively retain the wiper.