The chairman of hospital infection control experts Tristel sold a small chunk of his shares in the company late on Monday.Francisco Soler sold 250,000 shares in the dividend-paying company at a price of 75p per share on 31 October and on 3 November 2014 sold 100,000 more at the same price to gross a total of £262,500.The shares are currently trading off their recent all-time highs not far from 90p, having appreciated strongly in the last 18 months.Following these deals Soler, a founder shareholder of the AIM-listed outfit, still has family interests in a hefty 26.1% of the company.Soler recently took up the role of non-executive chairman again on an interim basis after Christopher Samler announced in October that he was stepping down after only three years in the role.Recent full year results showed pre tax profits more than tripling on turnover up 28% to £13.47m. The dividend for the full year was lifted fourfold to 1.62p - but Soler will miss out on a small fraction of his rewards due to this sale as the ex-dividend date is not until 22 November."There was demand for a modestly sized block of shares which the Soler holding met in order to increase the float and extend the shareholder register," a spokesman for the company said.Top Director BuysAbcam (ABC) Director name: Lady Louise PattenAmount purchased: 6,266 @ 403.27p Value: £25,269Top Director SellsTristel (TSTL) Director name: Mr Francisco Angel SolerAmount sold: 250,000 @ 75.00p Value: £187,500Tristel (TSTL) Director name: Mr Francisco Angel SolerAmount sold: 100,000 @ 75.00p Value: £75,000